Search results for "FRAM"
showing 10 items of 2142 documents
Revisit of RTS/CTS Exchange in High-Speed IEEE 802.11 Networks
2005
IEEE 802.11 medium access control (MAC), called distributed coordination function (DCF), provides two different access modes, namely, 2-way (basic access) and 4-way (RTS/CTS) handshaking. The 4-way handshaking has been introduced in order to combat the hidden terminal phenomenon. It has been also proved that such a mechanism can be beneficial even in the absence of hidden terminals, because of the collision time reduction. We analyze the effectiveness of the RTS/CTS access mode, in current 802.11b and 802.11a networks. Since the rates employed for control frame transmissions can be much lower than the rate employed for data frames, the assumption on the basis of the 4-way handshaking introd…
A System of Indicators for Evaluating Public Broadcasting Corporations
2018
We describe an operational procedure to build an integrated information system (IIS) for monitoring and evaluating the performance of public broadcasting corporations (PBC). The procedure grounds in a conceptual framework derived from evaluation models, and consists of two stages. The first stage is the selection, through expert judgment, of simple indicators that illustrate the most relevant aspects of the corporations. The second stage is the definition of a system of indicators related to each level of the hierarchy of objectives planned by the corporations. The system of indicators has two levels. The first level is a basic indicator system that allows description and monitoring of the …
Convective Excitation of Inertial Modes in Binary Neutron Star Mergers
2018
We present the first very long-term simulations (extending up to ~140 ms after merger) of binary neutron star mergers with piecewise polytropic equations of state and in full general relativity. Our simulations reveal that at a time of 30-50 ms after merger, parts of the star become convectively unstable, which triggers the excitation of inertial modes. The excited inertial modes are sustained up to several tens of milliseconds and are potentially observable by the planned third-generation gravitational-wave detectors at frequencies of a few kilohertz. Since inertial modes depend on the rotation rate of the star and they are triggered by a convective instability in the postmerger remnant, t…
Computational general relativistic force-free electrodynamics
2020
General relativistic force-free electrodynamics is one possible plasma-limit employed to analyze energetic outflows in which strong magnetic fields are dominant over all inertial phenomena. The amazing images of black hole shadows from the galactic center and the M87 galaxy provide a first direct glimpse into the physics of accretion flows in the most extreme environments of the universe. The efficient extraction of energy in the form of collimated outflows or jets from a rotating BH is directly linked to the topology of the surrounding magnetic field. We aim at providing a tool to numerically model the dynamics of such fields in magnetospheres around compact objects, such as black holes an…
Continuous-variable entanglement sharing in noninertial frames
2007
We study the distribution of entanglement between modes of a free scalar field from the perspective of observers in uniform acceleration. We consider a two-mode squeezed state of the field from an inertial perspective, and analytically study the degradation of entanglement due to the Unruh effect, in the cases of either one or both observers undergoing uniform acceleration. We find that for two observers undergoing finite acceleration, the entanglement vanishes between the lowest frequency modes. The loss of entanglement is precisely explained as a redistribution of the inertial entanglement into multipartite quantum correlations among accessible and unaccessible modes from a non-inertial p…
Shear design of high strength concrete beams in MRFs
2019
This paper presents the criteria for the shear design of high strength concrete (HSC) beams in moment resisting frames (MRFs). The formulation of an analytical model is provided for the case of beams with longitudinal reinforcement in the presence of transverse stirrups. The model is of additive type, in the meaning that the shear resistance of the beam is evaluated as the sum of several contributions. In particular, the contribution of concrete, longitudinal rebars, and transversal reinforcement are taken into account. Furthermore, for assessing the concrete contribution, a classical approach is followed, according to which two effects arise in the shear mechanism: the arc and the beam eff…
Deep and Meaningful E-Learning with Social Virtual Reality Environments in Higher Education: A Systematic Literature Review
2021
Deep and meaningful learning (DML) in distant education should be an essential outcome of quality education. In this literature review, we focus on e-learning effectiveness along with the factors and conditions leading to DML when using social virtual reality environments (SVREs) in distance mode higher education (HE). Hence, a systematic literature review was conducted summarizing the findings from thirty-three empirical studies in HE between 2004 (appearance of VR) and 2019 (before coronavirus appearance). We searched for the cognitive, social, and affective aspects of DML in a research framework and studied their weight in SVREs. The findings suggest that the use of SVREs can provide aut…
Renovación metodológica de teorías de la comunicación ante el EEES
2012
La implantación del Espacio Europeo de Educación Superior, impulsado en 1999, ha transformado la oferta de títulos de las universidades españolas durante los últimos años. Sin embargo, el nuevo catálogo de grados también debe ir acompañado de una actualización de las estrategias docentes. La renovación metodológica de las materias de carácter más teórico supone un reto que es necesario afrontar con la incorporación de propuestas de aprendizaje colaborativo y con el uso de nuevas tecnologías. En este artículo se analiza el diseño, la aplicación y los resultados que dio el desarrollo de la asignatura de Teorías de la Comunicación según un modelo orientado al aprendizaje de los estudiantes, co…
Study Crafting and Self-Undermining in Higher Education Students: A Weekly Diary Study on the Antecedents.
2021
The aim of the current study is to validate the adaptation of the job demands–resources theory to the study context. In addition, we introduce the concepts study crafting and self-undermining to the study demands–resources framework by examining the mediating role of engagement and exhaustion in the relationship between study characteristics and study crafting and self-undermining. Over four consecutive weeks, 205 higher education students answered a questionnaire about their weekly study demands and resources, their well-being (i.e., engagement, exhaustion), and their study crafting and self-undermining behaviors. Multilevel structural equation modeling (controlling for autoregressors of m…
Identification of Vulnerable Groups in Terms of Language Proficiency in Higher Education
2021
The language proficiency of university students is considered a key factor for knowledge acquisition and success in higher education. Recent research has revealed a connection between language proficiency and academic performance. Some studies identified certain groups of learners who show deficits in language proficiency when entering higher education and who can be considered to be vulnerable groups who need particular support. The present study analyzes the level of proficiency in the language of instruction among two vulnerable groups of students at the beginning of their university studies: (i) students with a refugee background and a mother tongue other than English enrolled in Englis…